pub fn civil_from_days(z: i64) -> (i32, u32, u32)Expand description
Proleptic Gregorian (year, month, day) for a day count z since 1970-01-01 (the inverse of
days_from_civil).
The calendar repeats every 400 years (146_097 days): chrono converts the day within its cycle
and whole cycles go back into the year (an i128 so no z overflows), which matches the
proleptic Gregorian answer the old hand-rolled code gave past NaiveDate’s ±262143 range.
1970-01-01 is num_days_from_ce 719_163.